Railway system

ABSTRACT

A railway system comprising a beam supported at spaced intervals along its length and having tracks extending longitudinally thereof at opposite sides, with cars adapted to travel on the tracks in paths along opposite sides of the beam. Eack track comprises a lower rail and an upper rail extending longitudinally of the beam at the respective side of the beam. Each car has lower wheels traveling on the head of the lower rail and an outrigger extending laterally from the car to the upper rail having a traveling tension-transferring interconnection with the head of the upper rail for holding the car upright. The heads of the two rails of each track lie in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below the said inclined plane. The system as disclosed further involves a special switching arrangement for the tracks, a special station feature based on the provision of an elevator in the car, and a special expansion joint between rail ends.

United States Patent 1191 Edwards 1 RAILWAY SYSTEM Lawrence K. Edwards, 565 Arastradero Rd., Palo Alto, Calif.

221 Filed: on. 1, 1973 1211 Appl. No.: 402,299

[76] Inventor:

Primary ExaminerM. Henson Wood, Jr.

Assistant ExaminerD. W. Keen Attorney, Agent, or Firm-Koenig, Senniger, Powers and Leavitt 1 June 24, 1975 1 1 ABSTRACT A railway system comprising a beam supported at spaced intervals along its length and having tracks extending longitudinally thereof at opposite sides, with cars adapted to travel on the tracks in paths along opposite sides of the beam. Back track comprises a lower rail and an upper rail extending longitudinally of the beam at the respective side of the beam. Each car has lower wheels traveling on the head of the lower rail and an outrigger extending laterally from the car to the upper rail having a traveling tension-transferring interconnection with the head of the upper rail for holding the car upright. The heads of the two rails of each track lie in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the I beam below the said inclined plane. The system as disclosed further involves a special switching arrangement for the tracks, a special station feature based on the provision of an elevator in the car, and a special expansion joint between rail ends.

25 Claims, 27 Drawing Figures PATENTEDJUN24 I975 3. 890 904 SHEET 1 FIG.I

PATENTEDJUN 24 I975 SHEEI FIG.4

PATENTEDJUN24 ms 3. 8 9O 904 SHEET 5 h x :h

/35 m /4/ /3 Ma RAILWAY SYSTEM BACKGROUND OF THE INVENTION This invention relates to railway systems, and more particularly to a mass transit railway system especially adapted for installation as an elevated system in urban areas.

The invention is generally in the same field as the systems shown in the following prior US. Patents: Nos. 841,653, 904,526, 3,096,728, 1,167,892, 3,083,649, 3,122,105, 3,194,179, 3,238,894 and 3,457,876.

SUMMARY OF THE INVENTION Among the several objects of the invention may be noted the provision of an improved railway system of a type in which cars are adapted to travel on one or both sides ofa beam; the provision of such a system involving a modular construction that permits relatively efficient, rapid and economical erection and removal of system components; the provision of such a system which is of economical construction, which is adapted to various layouts, and which is easy to maintain; the provision of such a system which enables ready incorporation of a third rail" for transmission of electric power to a car; the provision of an efficient switching arrangement for such a system, and particularly one that enables two-way traffic; the provision of an improved station accommodation for an elevated system based on the provision of an elevator in the car; and the provision of an improved expansion joint especially useful in the system.

In general, the system involves the provision of a beam with a track extending longitudinally of the beam comprising a lower rail and an upper rail extending longitudinally of the beam. In accordance with the invention, the heads of the rails lie in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below the said inclined plane. A car is adapted to travel on the track, and for two-way traffic, the beam may have a second track corresponding to the first on its other side. Other objects and features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (sheet I) is a side elevation of a fragment of an elevated railway system of this invention;

FIG. 2 (sheet I) is an end view of FIG. 1, showing a car on one side of the beam of the system;

FIG. 3 (sheet I) is a perspective of a fragment of the system showing a car with parts of the car broken away;

FIG. 4 (sheet 2) is a vertical transverse section of the beam, on a larger scale than FIG. 2;

FIG. 5 (sheet I) is an enlarged detail view showing a lower rail;

FIG. 6 (sheet 3) is an enlargement of the upper part of FIG. 4, showing further detail;

FIG. 7 (sheet 4) is a transverse section showing a lower wheel and an outrigger of a car;

FIG. 7A (sheet 4) is a view generally on line 7A7A of FIG. 7;

FIG. 8 (sheet 5) is a plan of the outrigger shown in FIG. 7;

FIG. 9 (sheet 5) is a view taken generally on line 99 of FIG. 8;

FIG. 10 (sheet 2) is an enlarged fragment of FIG. 7;

FIG. 11 (sheet 6) is a plan view illustrating a switching arrangement of this invention;

FIG. IIA (sheet 7) is a continuation of FIG. 11;

FIG. 12 (sheet 6) is a side elevation of FIG. 11;

FIG. 12A (sheet 7) is a side elevation of FIG. 11A;

FIGS. l3-I6 (sheet 6) are vertical transverse sections on lines I3l3 to 16-16 of FIG. 11;

FIG. 1'! (sheet 8) is a view of a station of this invention;

FIG. 18 (sheet 9) is a plan of an expansion joint of this invention;

FIG. [9 (sheet 9) is a side elevation of the FIG. 18 joint;

FIG. 20 (sheet 9) is a side elevation of one member of the joint;

FIG. 21 (sheet 9) is a bottom plan of FIG. 20; and

FIGS. 22-24 are sections on lines 22-22 to 2424 of FIG. 19.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT As noted above, this invention relates to a mass transit railway system, especially adapted for installation as an elevated system in urban areas. It features a slender common guideway, which may be double-tracked for two-way traffic, compatibility with a practical switch, avoidance of elevated stations in residential areas, and a modular construction that permits speedy erection or removal of the fixed installations. Additional advantages are economical construction, flexibility of layout, easy maintenance, and easy accommodation ofa third rail" for electrical power.

A key element of the system as herein illustrated is a triangular beam with a rail at each apex, which rails constitute the primary structure of the beam in addition to serving as rails for support and guidance of cars. At each lower corner of the triangle is a rail for support of the cars; at the top of the triangle are a pair of rails, es sentially back-to-back, each of which is interengaged by tension means extending from the car to hold the car upright. The webs of the beam may be either perforated or unperforated, depending on the preference of the user. In either event, they carry shear loads which arise from deadweight of the passing cars, torsion due to unsymmetrical loading, and deadweight of the beam itself.

In the preferred embodiment, the beam is constituted by prefabricated elements or modules, approximately 20 meters long, for example, laid end-to-end, with their ends resting on columns or supports which may be of various suitable configurations. As an expansion joint is desirable between most beams, there is no arrangement to transfer bending moments or vertical shear from beam to beam. In curves, the beam is banked or superelevated to the appropriate angle, and the length of the beam module is typically shortened (perhaps to 12 meters, for example) to accommodate the extra loads. Transition beam components are needed at the beginning and end of curved stretches, for reasons well known in the railroad art.

Cars pass along the side of the beam, traveling singly or in trains. It is contemplated that these cars will have an on-board operator and very little reliance on computers or other automatic controls; however, this choice has no bearing on the present invention. Each car has two slanting wheels near the bottom of the car and close to that wall of the car nearest the beam, which wheels are preferably steel-rimmed and doubleflanged to engage positively with the railhead. Propulsion and braking of the car is exclusively through these two wheels. For most applications, it appears desirable that these wheels and the associated motor/clutch- /geardrive/braking elements comprise a module that is installed in and removed from the car as a unit, that the entire module be spring-mounted to the car body, that the wheel not be steerable relative to the car body, and that the wheel incorporate elastic inserts between rim and hub in order to absorb sound and vibrations. These details do not affect the basic invention, however.

Inasmuch as the car's center of gravity is significantly offset from the main wheels, it is necessary to make provision for preventing the car from falling away from the beam. This is accomplished by use of a tension means or outrigger" extending from the car body above each main wheel to engage the upper rail, as noted above. The means of engagement may be rollers or slides, for example, and they may straddle the railhead or pass inside a special C-shaped railhead. The preferred embodiment uses a multiplicity of rollers in a modified whiffletree arrangement to carry the load without excessively large rollers or wheels.

The overturning moment on the car due to force of gravity is large and relatively invariant. Consequently. there is no need to provide additional rollers or the like to prevent the car from tipping in the opposite direc tion.

ln cross section, the car's main wheels and outriggers are arranged to direct loads toward the corners of the beam, thereby minimizing the need for secondary structure in the beams section. The webs and heads of the beam rails are oriented more or less symmetrically in line with these vectors. The outrigger load vector, being in tension, permits the use of occasional universal joints in the outrigger for ease of alignment and accommodation of tolerances. The outrigger vector could be horizontal; however there may be some advantage in having it on a gentle slope, the main benefit being that this causes the wheel loads to increase somewhat, thereby improving traction for propulsion and braking. Some rail transit systems have been marginal in this respect, especially in rainy weather; the configuration shown herein is believed to afford an improvement of nearly over the best duorail systems.

The construction described above is adequate for system applications where the car is entered from the outboard side or, in fact, any direction other than the beam side. However, studies have shown considerable merit in an arrangement where the station is placed "between the tracks", e.g., between oppositely bound trains, so that one platform can serve both. This feature requires a departure from the basic beam configuration at stations involving an increase in beam height to make it possible for passengers to enter the car from the beam side" without having to stoop underneath the upper rail, with a corresponding change in loadvector arrangements.

Other system studies have indicated that there is virtue in ground-level stations so arranged that there is no need to bring the beam down to ground level. A possible solution to this is to incorporate an elevator into the car.

Another attractive adjunct is the ability to service the beam and switches without resorting to (a) groundlevel service vehicles and the associated ladders or other elevating devices, or (b) service vehicles that travel along the guideway as passenger cars do, thereby complicating the normal passenger service. This is feasible by keeping the inside of the beam and switches clear as a passageway for maintenance personnel. By the same token, power lines and communication wires for the system can be mounted inside the beam and still be readily reached for maintenance or repairs.

With regard to the cars outrigger, it is necessary that this device satisfy several criteria as follows: First, to permit negotiation of horizontal curves, it is necessary that the group of outrigger rollers (or analogous slide or magnet) must be able generally to swing about a vertical axis relative to the car. In addition, it is necessary that certain rollers shift relative to the others to conform to the local curvature without roller overloading. (A slide, if used, must actually flex to avoid excessive localized bearing pressures.) Second, to accommodate vertical curves, it appears desirable to permit freedom about a horizontal axis analogous to that just discussed; this problem may be alleviated by using a somewhat greater radius for vertical curves. Third, it is desirable to minimize the cross-sectional dimensions of the roller or slide in order to minimize the section of the upper rail combination and also to simplify the design of the switch. To permit universal joints as already discussed, it is also desirable that the general assembly of rollers (or slides) be self-aligning about all three axes and in the vertical direction as well. It must also be fixed relative to the car in the transverse and longitudinal directions. Fourth, to avoid twisting the car as it negotiates the transition sections at the ends of curves, the two outriggers on each car must be coordinated so that one extends laterally as the other retracts laterally; thus the pair of outriggers maintain the desired rotational position of the car relative to the beam, without twisting the car itself. The present invention satisfies all of these criteria. It may be advantageous to provide a protected passage for the outrigger, possibly making the system less vulnerable to adverse weather, animals, vandalism, and accidental blockage, and to use one or more magnets on the outrigger to provide most or all of the required tension force. Use of these arrangements makes it virtually impossible to *derail" the outrigger from the upper rail because one nearly surrounds the other. The present invention may also provide for positive engagement between the car and the lower rail, by the use of hooks alongside the main wheels System studies shown that, with realistic turning radii and reasonable wheelbase in the car, there is no need to move these hooks in turns; i.e., they may remain fixed relative to the wheel axle.

It is desirable that the outrigger should at all times point its vector toward the intersection between the main wheel vector and a vertical line (or more correctly, a vertical plane) through the car's center of gravity. To accomplish this, it is desirable that the outrigger be attached to the car by means of a hinge located at this point. While this may be feasible in certain special applications such as freight trains, the present configuration is such that the hinge point falls near the center of a passageway. While a vertical hinge such as four-bar linkage may be used, the preferred arrangement utilizes a curved track (or pair of tracks) in the available space closer to the cars inboard walls, as will appear. This curved track is configured and positioned so as to form a radius about the desired hinge point. Thus the outrigger, with a roller or slide at its inboard end, will transmit the tension vector to the car in the desired manner. Studies show that it has a powerful self-centering action. Continuing the discussion of carto-beam relationships, it is plain that, within rather broad limits, the bottom of the car could be substantially above or below the bottom of the beam. Plainly, in densely built-up areas, both must be at least high enough above street intersections to clear trucks and buses, i.e., about 4.5-5 meters, for example, above street level. An arrangement with the two bottoms essentially co-planar, has the following advantages:

short columns and easy erection of the guideway;

minimum interference with overhead wires, which run generally horizontally;

minimum vertical dimension in the clearance passage when the system penetrates buildings: it is especially advantageous to confine this penetration to a single story of a building;

small, convenient tunnel cross section;

small vertical clearance increment between two crossing lines of the same system;

short stairways for passengers; short travel for elevators;

minimum overturning moments imposed on columns and foundations due to wind loading on the combination of guideway and cars: (the present arrangement reduces the magnitude of the wind force as well as its moment arm above the ground);

passengers can see out" on both sides of the car: (the top of the beam is approximately at eye level of seated passengers).

As will be discussed further, considerations of switching impose a clearance requirement on the car such that nothing on the car should penetrate the envelope schematically illustrated by the phantom line X in FIG. 4. The vertical portion of the line is dictated by (and is a function of) such practical matters as clearance between cars traveling on opposite sides of the beam, clearance at stations, and the like. The envelope is penetrated locally at the outrigger and at the main wheels; these penetrations, in turn, become constraints on the design of the remainder of the system, particularly the switch.

The preferred embodiment of the system employs conventional electric propulsion of the cars, with associated regenerative braking, substantially in line with modern practice in rapid transit lines and streetcars. This requires third rail" power transfer from the guideway to the cars. FIG. 6 shows the preferred arrangement in cross section, with a third rail for each direction of traffic. These third rails are fastened to the upper primary rails (with insulation therebetween) at intervals of perhaps 1 meter, for example. The main power conductor, which services both directions of traffic, may be secured inside a steel protective enclosure, which is an integral element of the beam structure. Cross-feed between the main power conductor and the individual third rail is located at the joint from one beam module to the next, and may employ relays, fuses, and other devices according to the preference of the electrical system designer. Power is picked up by the car via a roller or wiper affixed to the outrigger carriage. Placement of the upper rail with its web generally horizontal, in conjunction with a sloping outrigger vector, affords extra space between the rail web and the lower rollers, which space is desirable to assure sufficient electrical gap around the third rail. This placement of the third rail was selected after considering many factors including moisture condensation; adverse weather; accumulation of grime; inspection and clearing; accidental damage to the beam; mechanical and electrical convenience; electrical hazard to workers, passengers, and animals; and compatability with the switch.

A gap is preferably provided between the bases of the opposite upper rails (as appears in FIG. 6). This gap permits extension of utility standards or the like upward from the center of the beam. It also permits solid mounting of a weather shield (shown in FIG. 6) and permits a strong, rugged connection between the rails and the remainder of the beam structure, particularly in the presence of transve rse loads imposed on the rails. To facilitate this construction it may be necessary to incorporate transverse bulkhead-like members (not shown) at spaced intervals along the beam, which members are attached to both rails and possibly to the protective enclosure.

In a preferred arrangement, the car has some twenty seats, the majority of which are in pairs facing the direction of travel. A longitudinal passageway is included to provide for standees, to facilitate emergency escape, and to minimize the number of external doors on the car. This passageway is placed closer to the beam than the double seats, to assure that dense loads (i.e., standing passengers) are closer to the beam than the lowdensity loads (i.e., seated passengers). Additional seats are placed inboard of the passageway; system studies show that bench-type seats have several incidental advantages over single seats facing forward. These additional seats occupy the longitudinal space between the wheels, except for space at the inboard doorway. The wheels and their associated motor/geardrive/clutchlbrakes are preferably assembled into a module which is in effect a one-wheel truck" where truck is used in the lexicon of US. rapid transit, synonymous with bo gie" in Europe. This module or truck is mounted to the car body so that there is restrained vertical freedom between the two. There is no need for the truck to rotate relative to the car about any axis; this is a considerable simplification in comparison with conventional rail transit vehicles. Provision is preferably made for vertical freedom of the truck while restraining the truck in two directions and three rotational axes. Details of the geardrive, clutch, and brakes may be chosen from any of several well-known methods. Further, the wheel may incorporate elastic inserts between the hub and the rim; again, there are several existing solutions from which to choose. it is evident that this arrangement keeps the heaviest single element of the car, i.e., the truck, very close to the center of the beam to minimize overturning moments. Such measures reduce demands on the beam, columns, and foundations in terms of rigidity as well as strength. Also, it may be desirable to transfer the vertical load between truck and car in a flexible, damped manner, and also to incorporate load-leveling features. Components for this purpose may be enclosed in a portion of the car body which has structural as well as safety/cosmetic functions to perform. This enclosure may include removable panels inside the car for convenient inspection and servicing of said components while they are in place.

Doors and windows of the car are conventional and are incidental to the present invention. To take advantage of a "center platform station, as already discussed, an inboard door is favored. This also facilitates emergency escape, particularly in tunnels or above bodies of water.

Couplings from car-to-car can be of modern rapidtransit design, with integral electric circuits and possible pneumatic connections as well. Placement of the couplings beneath the end door sills appears to be superior to the other locations studied, particularly from the standpoint of impact on the car-to-car passageway. In the preferred arrangement, which has an elevator at the front of the lead car, it does not appear practical (or necessary) to incorporate a coupling at the front of the lead car. However, it is desirable to incorporate an airbag anticollision device on the front of the lead car and to provide mating surfaces on the rear of every car to cooperate with this air-bag.

The general section of the beam could be a truncated isoceles triangle (i.e., a four-sided figure with sloping sides and horizontal top and bottom), for example. However, this may compromise the structural simplicity of the beam and, in particular, may introduce the need for shear-carrying elements in the cross section. Such elements may be objectionable not only because of their cost and weight but also because they would tend to block the internal service passageway. Furthermore, if the two upper rails are moved a substantial distance apart, there may be a loss in their combined stability as compression members. (These rails are preferably the main compression-carrying elements for general beam bending under gravity loads.) Finally, such a section would force the massive elements of the car to be located farther from the center of the beam, adding to loading on the columns and foundations as well as the beam itself.

The webs of the beam, i.e., the shear-carrying elements on the three sides, may be porthole" elements as will appear. However, the webs could be thin solid panels (probably gaining structural efficiency at significant cost in attractiveness, internal servicing convenience, and possibly noisiness) and could even consist of thin-webs-plus-stiffeners. They could also be classical truss-like elements or a lattice of diagonal elements achieving the same result in conjunction with suitable stiffeners.

Hand and computer analyses have shown that, as the car moves along the beam, deflections at the car's center of gravity (i.e., some one and one-half meters, for example, from the center of the beam) are dominated by two phenomena: first, bending of the beam module, as governed by its length and the amount of cross section in the steel rails; and second, twisting of the beam module, as governed by the shear rigidity of its three webs. Studies also show that, when these two contributions are essentially equal, there is almost no interaction between two cars (or trains) passing along opposite sides of the beam and dynamic problems are minimized. As a practical matter, this desirable result can be achieved by judicious design of the webs.

The connection from beam module to beam module has been studied and it appears desirable to minimize the structural interdependence first, because there is no practical way to avoid expansion joints in long,

straight runs of elevated track and second, because it is desirable to replace a damaged beam module with a minimum of intricate work at the job site. Studies indicate that the critical consideration in alignment from one beam module to the next is the lateral alignment of the upper rails. Misalignment here, particularly in con junction with expansion-joint gaps up to 15 mm., could be harmful to the rollers of the outrigger. Therefore, it is proposed to couple one beam module to the next in the vicinity of the upper rails, with a coupling that transfers lateral shear but does not interfere with expansion. Studies suggest that the coupling can be so installed as to introduce a step-down" or horizontal offset from one beam module to the next which varies according to the width of the expansion gap, and is matched to the roller radius. For example, with a roller radius of 55 mm. and a gap of 15 mm., the ideal stepdown is approximately 2 mm. This offset can decrease linearly to zero as the expansion gap closes, to minimize wear and noise. The same mechanical arrangement is appropriate for reverse traffic on the opposite side of the beam; however, this should not be attempted when it is desired to run trains in reverse at high speed, as in shuttle applications.

As will be discussed below, there is advantage in transferring longitudinal loads from one beam module to the next. The load-transfer device must resist rapid loading, such as takes place when trains accelerate and decelerate, but must not resist gradual changes in the spacing from beam module to beam module due to temperature fluctuations. This may be accomplished by introducing a special piston-and-cylinder device generally similar to a hydraulic actuator but without external hydraulic ports or controls. Instead, there are chambers on either side of the piston. With a restricted passage through (or around) the piston and a fluid" that creeps at a very slow rate, these contrasting requirements are satisfied. The fluid can be a very viscous substance such as pitch or a suitable silicone. The piston is attached to one beam module and the cylinder to the other, to transfer the loads in this manner. Practical considerations dictate that the piston pass through both ends of the cylinder, so that the combined volume of the two chambers is always the same, regardless of the extension. Thus, the volume of contained fluid is always the same, and external fluid storage is avoided. This device is preferably located at the center of the beam section, above or below the service passageway.

The columns may generally be of conventional construction, either concrete or steel, although steel construction may provide a more slender appearance. Normally, one column is placed beneath each beam module-to-module joint. Studies show that, for realistic weight and proportions of beam modules and cars, it will be necessary to fasten the beam module down at each ofits four "corners" (as seen in plan view) regardless'of design criteria for wind and earthquake loads. This is preferably accomplished by a group of vertical bolts at each corner of the beam module; this means, in turn, that there are four corners and four groups of tiedown bolts at each column. The attachment must also accommodate expansion in the gap from beam module-to module, perhaps as much as 20 mm. In order that braking and acceleration loads may be transferred from beam module to column, at least one of the two beam modules must be longitudinally constrained to the column.

As previously discussed, it is advantageous to transfer the (relatively small) transverse shear loads from one beam module to the next via a special coupling. Therefore, only one of the two modules should be anchored transversely to the column. There are many obvious ways to accomplish this while satisfying the other constraints just discussed.

An elastic insert between the beam modules and the columns may be helpful to reduce noise, and can also assist in smoothing the ride". Such elasticity, however, must not permit sloppiness in the vertical or lateral alignment from one beam module to the next, or rolling noise and possibly other difficulties would be encountered. It appears preferable, therefore, to anchor the two adjacent beam modules down to a common steel block, which block is prevented from rotat ing about a transverse axis (i.e., transverse to the beam) by the nature of the beam-to-block attachment itself, preferably by engagement of the tie-down bolts discussed previously. Such a block is situated at the outboard extremity of the columns cross-head, and the elastic insert appears between the cross-head and the block. Additional features may be incorporated in the block installation to provide fail-safe metal-to-metal engagement in the event of failure of the elastomer, to provide vertical adjustment for tolerance accumulation or slight settling of the foundation and to permit all metal-to-elastomer bonding to be done in the factory.

At the base of the column, the preferred arrangement involves a horizontal concrete or steel pad to support the column, with a multiplicity of projecting vertical studs to permit anchoring the base of the column. Selective shimming at the interface permits adjustment of the vertical position of the column and/or transverse and longitudinal adjustment of the top of the column, to allow for assembly and erection tolerances. The foundation must have sufficient "footprint" to carry the weight of columns, beam modules, and cars; suffcient transverse moment-resisting capability to account for lateral loads due to winds, earthquakes, and centrifugal forces in curves; and sufficient longitudinal moment-resisting capability to allow for earthquakes as well as forces arising from starting and stopping the trains. This last consideration is greatly relieved by the beam-to-beam longitudinal restraint, previously discussed, inasmuch as this permits distributing the longitudinal braking forces of a multi-car train among perhaps six columns instead of only one or two columns.

In a preferred arrangement, a concrete fender is placed around the base of the column to prevent tampering with the adjustments, to protect the columns from errant automobiles and trucks, and to enhance the appearance of the assembly. These concrete fenders can be pre'cast in halves for easy installation or replacement, and can incorporate provisions for plants or other landscaping aids.

When the guideway curves as much as 60 or thereabout in a relatively short distance, loading per unit length on the beam modules, columns, and foundations increases to such an extent that the module length and consequent spacing between the columns and foundations should be shortened by perhaps one-third. In such situations, it is desirable to rotate the entire beam section. giving the equivalent of superelevation as it is known in conventional railways. In this connection the cross-head of the column is normally inclined according to the desired angle of superelevation; the upright element of the column may be inclined or not depending on such considerations as appearance and available space. For tight curves, the typical expansion joints between beam modules may be eliminated at some or all 5 junctions because moderate flexing of the upright elements of the columns will absorb the slight shifts in the elevated guideway.

Now referring to the drawings, first more particularly to FIGS. 1-4, an elevated railway system of this invention is illustrated as comprising a beam or grider l supported at spaced intervals along its length and having a first track Tl extending longitudinally thereof at one side and a second track T2 corresponding to the first track extending longitudinally thereof at the other side. Cars such as indicated at C are adapted to travel on the tracks in paths along the respective sides of the beam. Each track comprises a lower rail R, and an upper rail R The car has lower wheels 3 traveling on the head 5 of the lower rail R, and tension means indicated generally at 7 extending laterally from the car to the upper rail R and having a traveling tension-transferring interconnection at 9 with the head 1] of the upper rail for holding the car upright. The heads of the rails of each track are in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane. Thus, the first track T, comprises the lower rail R, and the upper rail R (first and second rails) at one side of the beam with their heads in an inclined plane, and the second track comprises the lower rail R, and upper rail R (third and fourth rails) at the other side of the beam symmetrically opposite the first and second rails, the heads of the third and fourth rails lying in a second plane inclined oppositely to the first plane with substantially all of the beam below said second plane.

More particularly, the beam 1, in transverse cross section, is generally in the form of a hollow triangle (see particularly FIG. 4) having a base indicated at 13 and opposite sides 15 converging toward one another in upward direction from the ends of the base to an apex at A. The two lower rails R, extend longitudinally of the beam at the ends of the base B, i.e., at the lower corners of the triangle, each arranged with the wheelengageable outer surface 50 of its head 5 spaced outwardly from the respective side of the beam and inclined downwardly in outward direction with respect to the beam. The upper rails R, extend longitudinally of the beam at the apex A of the triangle, and extend laterally outwardly in opposite directions from the apex with the inside surfaces 11a of their head 11 facing inwardly with respect to the beam.

The lower rails R, constitute lower chord members for the beam stressed in tension under the dead load of the beam and the live load of cars traveling along the beam. The upper rails R constitute upper chord members for the beam stressed in compression under said dead and live loads. The beam also comprises bottom web means at its base 13 between the two lower rails R, and side web means at its sides 15 between the lower rails and the apex A. The web means takes dead and live load shear strains and asymmetric live load torsional strains.

More particularly, the beam 1 for a continuous length of the system comprises a plurality of basic beam or girder modules each designated 1A in FIG. I, each of these basic modules being suitably supported at its ends at the requisite elevation on suitable standards or pylons 17 (which may be of steel or concrete construction) having T-heads 19 for bearing engagement by the base I3 of the module at its ends. Each module may have a length of 20 meters and each pylon may be 4.5 meters high, for example.

In greater detail, the lower rails R of each module 1A are identical, each being a standard railroad rail (e.g., a 90 lb. rail) having a flange or base 21, a web 23 and a head 5 (see FIG. 5), the outside surface 5a of the head constituting the wheel-engageable surface of the rail. The lower rails are secured together by the base or bottom web means 13 in spaced-apart parallel relation, this web means including crossbars such as indicated at 25 in FIG. 5, which are preferably tubular bars of rectangular cross section, with the webs ofthe rails inclined upwardly and outwardly as appears in FIGS. 35 from the ends of the crossbars, preferably at an angle of generally 60 to the horizontal as indicated. The crossbars are cut away at each end as shown in FIG. 5 to engage the flange 21 of the rail R the crossbars and rails R being suitably welded together. The upper rails R of each module are identical, each having a flange or base 27, a web 29 and the head ll. The upper rails may be of approximately the same weight per yard (e.g., 90 lb.) as the lower rails. The upper rails of each module are mounted in back-to-hack spaced relation on a cylindrical tubular supplemental upper chord member 33 constituted by a steel pipe extending the full length of the module, with one edge of the flange of each rail bearing on and welded at 35 to the top of the pipe and with the flanges 27 extending vertically upward from member 33. Pipe 33 may serve as a conduit for an electric power bus 38 for the system. The webs 29 of the rails R extend generally horizontally, as shown. Each upper rail has the two inwardly facing tracking surfaces lla on the inside of the rail head 11, these two surfaces being angled relatively to one another as shown in FIG. 6, with the upper surface 110 inclined upwardly and outwardly at a small angle, e.g., 5, off vertical, and the lower surface 11a inclined downwardly and outwardly at a somewhat larger angle, e.g., 15, off vertical. A guard or cover 43 for the upper rails is mounted on the upper edges of their flanges 27. The web 29 of each upper rail R carries on its bottom a third rail 45 for supplying electric power to the cars, this third rail being insulated from the web as indicated at 47 in FIG. 6, and suitably connected to the bus 38 at periodic intervals along the track.

The webs at sides 15 of each module IA are consti tuted by plates which may have openings or portholes 49 therein at intervals along their length. These web plates 15 extend throughout the length of the module, each having its lower edge 51 received in the inside corner of the respective lower rail R at the juncture of its web and flange (see FIG. 5) and being suitably welded to the lower rail. Each side plate 15 angles upwardly and inwardly from the respective lower rail and has its upper edge engaging the respective side of the pipe 33 and welded thereto as indicated at 53 in FIG. 6. The base or bottom web 13 comprises a bottom plate 55, which may correspond to side plates 15, welded to the bottom of the crossbars, this bottom plate 55 extending throughout the length of the module. The bottom plate may have grilles 49a in its portholes 49. Rails 57 providing a service track for a service vehicle may be mounted on the crossbars 25 extending throughout the length of the module. While the side webs I5 are shown as plates having the holes 49 therein, and the bottom web 13 is shown as comprising plate 55, it will be understood that these webs may be of other structural form, e.g.. trusses. and the term web is intended to cover this.

The car C comprises a frame having inboard and outboard sections (inboard being toward the beam and outboard" being away from the beam), the inboard section being indicated at 59 in FIG. 7, with a floor 6] extending between these sections, and an enclosing shell 63. A preferred interior arrangement for the car is shown in FIG. 3. Generally, the car will have two lower wheels such as indicated at 3 in FIG. 7 on its inboard side adjacent its ends (one wheel ahead of and the other behind the center of the car). Each of these lower wheels 65 is on an axle 67 journalled in bearings 69 in a truck 7] pivoted on a pin 73 extending horizontally on the inboard side of the car at about midheight of the car. Each truck 71 and wheel 65 carried thereby is accommodated in a recess 75 in the inboard side of the car. The truck is preferably mounted for some degree of damped vertical freedom, as by means of upper and lower links 78 and 79, with a conventional air/oil shock absorber 80 functioning as a damper (and which may also be a load leveler). The truck is generally positioned so that the plane of the wheel 3 is in the inclined plane of the web 23 ofthe respective lower rail R each lower wheel thereby bearing properly on the head of the respective lower rail R The lower wheels 3 are preferably steel-rimrhed and double-flanged positively to engage the head of the rail. The truck for at least one of the lower wheels carries a drive module M comprising an electric motor drive including an output shaft 81 geared at 83 to the lower wheel. The drive module may also include suitable braking means for the wheel. The truck 71 may include hooks such as indicated at 85 extending under the head of the lower rail R to hold the wheel against rising off the rail.

Each car carries a tension means or outrigger 7 above each of its lower wheels 3, the tension vector being indicated at TV in FIG. 4. Also illustrated in FIG. 4 are the gravity vector GV of the weight of the car and the vector WV of the weight of the car on the lower wheels. The tensiontransferring interconnection 9 of each outrigger 7 comprises an upper series W, of rollers W which engage the upper tracking surface 110 of the respective upper rail R and a lower series W of rollers W which engage the lower tracking surface Ila of the respective upper rail. Each series of rollers is carried by an I-beam 87, the web 89 of this beam being slotted as indicated at 91 in FIG. 9 with the rollers mounted on shafts 93 journalled in the flanges 95 of the l-beam and accommodated in the slots 9]. The two I-beams (carrying the two series of wheels) are mounted in back-toback relation inclined to each other at an angle corresponding to the angle between the planes of the two upper and lower tracking bearing surfaces 11a of an upper rail R (e.g., 20) on an elongate truck 97. The latter has a portion 99 of generally C-shape in cross section which freely straddles the head 31 of the respective upper rail, and which has upper and lower lugs IOI and 103 above and below the web of the respective upper rail to which the I-beams are secured. The lugs extend into slots 91 in the webs of the I-beams, and the l-beams are secured to the ends of the lugs via pins 105 extending between the flanges 95 of the I-beams. Three sets of lugs and pins are shown for each I-beam, and the holes for the central pins of the three may be slightly oversize for limited flexing ofthe l-beams. The truck 97 has an endwise extension 107 from its C-section portion carrying a power pickup 109 for engagement with the third rail 45.

The truck 97 carrying the upper rollers W is mounted for up-and-down movement and in-and-out movement relative to the car C by means indicated generally at 111 in FIG. 8 comprising a carriage 113 having rollers 115 at its ends adapted to roll up and down in arcuate channel section tracks 117 mounted on members 119 of the inboard section of the car frame at the fore and aft ends of the recess 75 in the inboard side of the car. These tracks are curved on an are centered in an axis 123 (see FIG. 7) which generally coincides with the junction of vectors GV, TV, and WV in FIG. 4. The truck 97 is mounted on the carriage for movement in and out relative to the carriage (laterally relative to the car) by means comprising a drag link 125 and a hydraulic equalizer cylinder 127. The link 125 is pinconnected at one end as indicated at 129 to the end of the carriage 113 toward the respective end of the car and at its other end as indicated at 131 to the truck in such manner as to permit inward and outward movement of the truck relative to the carriage. The cylinder has one end pin-connected at 133 to the carriage and has its piston rod 135 extending from piston 137 therein pin-connected at 139 to the truck. The inner end of the cylinder is vented and the outer end is adapted to be supplied with hydraulic fluid at relatively high pressure (e.g., 1800 psi). The pressure ends (the outer ends) of the cylinders for the fore and aft upper wheel sets are interconnected by an equalizer line 141 for anti-twist compensation.

Unconventional transit systems have always encountered great difficulty for lack ofa practical switch, particularly one that is suitable for two-way traffic. To permit discussion of this subject, it is appropriate to establish a convention to identify the several lines. As shown in FIGS. 11 and 11A, C indicates the common line where cars normally approach a branch or point of divergence. After divergence, one line is identified as A and the other B. In the reverse direction, where branch lines converge, the same letters are used with a prime'. Thus, there are six different tracks and 12 different rails involved in the situation shown in FIGS. 11, 11A, 12 and 12A.

Conventional duo-rail systems manage switching by keeping all rails in a common (essentially horizontal) plane. Only the flanges of the car wheels penetrate this plane. The result is practical, if not absolutely safe; there have been occasional head-on collisions between opposing traffic, and the safety precautions to avoid such collision are expensive and time-consuming. No unconventional transit system has approached the degree of safety and practicality of duo-rail switches, particularly where two-way traffic is needed. It appears that unconventional systems encounter switching trouble because their cars occupy much more of that vertical regime occupied by the tracks than is true for duorail systems, where nothing more than wheel flanges extend below the top of the rails. Consequently, the movable part of the switch must move much farther laterally (and is more difficult to support mechanically) than is true for duo-rail.

Many current unconventional systems employ a "passive" switch in which the guideway is U-shaped and the car hugs either the left or right wall of the U when it passes through a switch. This can be expected to succeed reasonably well for one-way traffic, but, when it is attempted to do the same thing for two-way traffic, the occupation of the same vertical regime by the wall and much of the vehicle creates an almost insurmountable problem.

This invention involves a switch which is believed to solve these problems, avoiding some of the disadvantages of dual duo-rail switches in the process. In the interest of compactness, it takes advantage of the superior hill-climbing capability of the suspension arrangement previously discussed.

The underlying concept in this switch is threefold. First, the various tracks for the C-A B combination should be kept coplanar until they have separated sufficiently to go their own way. Second, there is no need to keep the various tracks of the C-A-B' combination in the same plane as the C-A-B group; in fact, it is ad vantageous if they do not. Third, penetrations by the car into the switch plane should be few and local in order to keep mechanical motions small and simple.

The two rails R, and R to which a car of the present invention attaches are in a plane that slopes to the horizontal, for example. The switch concept of this invention is to keep all rails of the C-A-B combination in this same sloping plane, and to do likewise with the C'- A-B' group. To facilitate further discussion, an addi tional convention will be adopted: .A" will be defined as the branch that is higher, and B the lower. It will be seen that the A line may continue straight ahead, or turn left or right, as the situation demands; the same is true of the B line.

A switching system of this invention for lines C-C', AA' and 8-3 is illustrated in FIGS. 11, 11A, 12, 12A and 13-16. Lines C-C' are constituted by the tracks T, and T, on opposite sides ofa first beam ICC. Lines A-A are constituted by the tracks T, and T, on opposite sides ofa second beam 1AA, and lines 13-13 are constituted by the tracks on opposite sides of a third beam lBB. As shown, beams ICC and 188' in effect constitute a continuous double-track straight line and beam 1AA constitutes a double-track branch line curving away from the ICC lBB' combination. It will be understood, however, that beam 183' may be a dou ble-track branch line curving away from beam lCC' oppositely to beam 1AA. The tracks T, and T of all of the beams are generally at the same angle of inclination as heretofore described (e.g., 60 to the horizontal). At SW, is indicated a first means for switching cars between line C (the first track T, of beam ICC) and line B (the first track T, of beam lBB') or line A (the first Track T, of beam 1AA), and at SW is indicated a second means for switching cars between line C (the second track T of beam ICC) and line B (the second track T of beam 18B) or line A (the second track T of beam 1AA). The switching means SW, comprises a descending track section 151 and an ascending track section 153 having a crossover at 155, with a movable track section 157 between line C (the first track T, of beam ICC) and the respective descending and ascending track sections 153 and 155. The switching means SW, is identical to the means SW, (but for lines C'-B- A). The descending and ascending track sections 153 and 155, in any vertical transverse plane along their length, are generally at the same inclination as the tracks of the beams and, in vertical transverse planes progressively from beam ICC to the crossover 155, are on the sides of triangles of progressively increasing size, as illustrated in FIGS. 13-16.

Beam ICC (with lines CC at opposite sides thereof) in effect terminates at a station 5,. FIG. 13 shows the cross section at station 13, corresponding to the stan dard beam cross section illustrated in FIG. 2. Between station 5, and the movable track section I57 is a relatively short generally horizontal extension 159 of beam ICC of progressively increasing, generally triangular cross section from station S, to its end at a station designated 5,. Tracks T, and T at opposite sides of extension I59 diverge gradually away from one another, as viewed in plan in FIG. 11, from station 8, to station 8,, but remain generally horizontal as viewed in elevation in FIG. 12. The movable track sections 157 of the switching means SW, and SW, lie on the sides of a beam 161 extending from station S, to a station designated 5,, this beam being of progressively increasing, generally triangular cross section from station S, to S The crossover 155 is at a station designated 8,. The descending and ascending track sections 151 and 153 of the switching means SW, and SW, lie on the sides of a beam I63 extending from station 5,, to a station designated 8,, this beam being of progressively increasing, generally triangular cross section from station S, to station 8,. At station 8,, lines B and B are spaced apart relative to one another in plan, and lines A and A lie side-by-side between lines 8 and B' as viewed in FIG. 11, and lines A and A lie above lines B and B as viewed in FIG. 12. Beyond station 8,, line B passes under lines A and A and lines B and B' converge toward one another, resuming their normal relationship on opposite sides of beam 183' at a station S, (see FIG. 12A). Lines A and A are in their normal side-by-side relationship at station S, and are shown as curving away from lines B and B on a curved beam 1AA (see FIG. 11A).

The result, then, is a compact and practical switch arrangement for two-way traffic with an advantage not achieved even in dual duo-rail switches; namely, cars of the opposing lines never occupy the same point in space, so that I) head-on collisions are impossible; (2) there is no need to resort to time-sharing, signalling and other precautions at this point; and (3) traffic-carrying capacity on the two opposing lines is greatly increased.

As noted above, an elevator may be provided in a car, with the attendant advantages of avoiding the expense, visual impact, and inflexibility associated with elevated stations. This is particularly true for stations in neighborhood areas, where only a few people may desire to get on or off a given train (a reasonable assumption provided stations are not far apart and service is frequent).

At ground-level stations, it is possible to place elevator shafts on each side of the track (one shaft for each direction of traffic), which shafts logically have vertical tracks to guide the elevator cab, a retractable cover to keep out snow and thrown objects, and doors at ground level to prevent unauthorized entrance. Even though the shaft structure may be of glass or transparent plastic, it may be visually objectionable. The shaft may also be rather expensive and a maintenance problem, especially if it is transparent.

An alternative is to use a novel guard means of this invention which serves two main purposes: first, it assures that people and pet animals cannot be injured by the descending elevator; and, second, it gives limited guidance to the elevator as it descends.

By straightforward mechanical design, the elevator can be suspended and kept level by a combination of cables as the cab is lowered to the ground or floor level, all of these cables and their associated drives and brakes being part of the car and controlled by an operator on the car. Redundancy in the cables, drives, and brakes may assure adequate safety. The guard means is designed to occupy the space that is needed for the descending elevator to keep people out from under the descending elevator, and to surrender that space in a safe manner as the elevator descends. The top of the guard means also engages the bottom of the elevator to prevent the elevator from swaying due to winds or other physical disturbances, and in fact guides the descending elevator to align with a recess in the station platform, so that the floor of the elevator will be at platform level when passengers board and de-board.

In its most rugged anad elementary form, the guard means is a rigid (possibily transparent) shell extending high enough above the ground to preclude accidents and mischief about the top. It has a pointed top to avoid the accumulation of snow (and other objects) and also to facilitate engagement and alignment with a conical recess in the bottom of the elevator. Beneath the shell is a recess in the station platform or floor of appropriate cross section and depth to receive the entire guard means shell. Also provided is a spring mechanism to overcome the weight of the shell and thus cause it to be up except when forced down by the weight of the elevator. This spring mechanism can be refined to offset a large fraction of the elevators empty weight, thereby saving energy demands in the elevator drive mechanism. It may also include an accompanying damper to keep the elevator from descending too fast, and possibly a remote-controlled brake to stop the elevator's descent in the event of certain mechanical failures aboard the car. Finally, the mechanism can be retracted or extended by remote control to inform travelers at a glance whether the transit system, or at least a particular station, is operating.

In places where vandalism is not serious, it is possible to reduce the depth of the hole in the platform and improve the appearance of the guard means as shown in FIG. 17. This embodiment would have the same hard, pointed top as the basic shell already discussed; it would also have substantially the same springs, dampers, and other functional options as discussed there. The essential difference would be a pliable rather than a rigid sidewall for the shell, which sidewall would telescope or otherwise collapse (e.g., in accordion manner) as the elevator descends. By giving the shell suitable flexibility and with suitable control of escaping air (as by controlled porosity of the shell fabric), the shell can be caused to swell as it is compressed from above, thereby assuring that the necked-down profile of the shell does not permit people or pets to enter the forbidden zone as the elevator descends.

In FIG. 17, the beam is again indicated at I and a car at C. The elevator is indicated at 171 (see also (FIG. 3) and is shown as having a conical recess 173 in its bottom. Any suitable mechanism may be provided for raising and lowering the elevator. FIG. 17 illustrates two guard means M, and M, at a station 175 for cars on the two tracks T, and T of the beam 1. Each of these is illustrated as of the collapsible sidewall type (e.g., adapted to collapse in accordion manner). Suitable spring means (not shown) is provided inside each guard means normally to extend it to its raised extended position as shown for guard means M, in FIG. 17. When so extended, the guard means is of sufficient height to exclude people from the area under a descending elevator at the station 175. Each guard means has a conical top 177 serving in conjunction with recess 173 in the bottom of the elevator 171 as lntersngagesbls alignment means for thepurpose above described. A car C is stopped at the station 1'75 with the elevator above the respective guard means M, and M,, and the elevator then descends for ingress and egress of passengers. As it descends, it engages the top of the guard means and pushes it downwardly into a recess 179 in the floor or platform 18! of the station, as shown for the guard means M,. When the elevator ascends, the guard means moves back up to its raised position.

Thermal expansion between successive beam modules may cause a gap approaching 20 mm. It is desirable that the beam modules be placed and interconnected so as to minimize wear and tear on rollers of the outrigger in this situation. it follows, then, that the maximum gap at the lower rails must exceed that of the top rails by whatever amount is allowed for tolerances in fabrication of the beams, otherwise tailoring of the beam modules would be required in the field. Furthermore, as a practical matter, it is important to be able to use straight beam modules in situations where the guideway alignment demands extremely gentle curvature (which may be vertical as well as horizontal). This consideration adds further to the gap at the lower rails, if the upper-rail gap is to be kept at a minimum. In fact, the nominally straight beam modules must be made with both lower rails slightly fore-shortened in order to permit lateral and/or downward curves without trimming in the field.

Preliminary studies indicate that it is both desirable and feasible to permit a combined allowance of :25 mm. for such tolerances and alignment provisions, in addition to an allowance of some 18 mm. for expansion. This must be done by inserting some sort of bridge means between the two beam modules. This bridge means must satisfy several additional requirements:

a. The assembly should also allow for vertical and lateral misalignment from one lower rail to the next. (Some misalignment is inevitable inasmuch as the upper rails and both lower rails are integral parts of the beam module, without adjustment provision.)

b. it must carry the design rolling loads with allowance for impact and fatigue, and without significant deflection.

c. It must carry moderate lateral loads, to allow for winds and other contigencies.

d. it must be securely attached longitudinally in order to transfer acceleration and braking forces to the main guideway structure.

c. It should not have excessive gaps re the rolling wheel, or as viewed by operators, passengers, and pedestrians on the ground.

f. It should, if at all practical, present suitable surfaces and have adequate strength to resist the same emergency loads for which the car's safety hooks are designed.

g. Any relatively complex mechanism, if needed, should be on a removable part rather than on the beam modules to provide for correction of developing defects and/or improvement of the design from time to time.

h. The construction should avoid loose fits of separate parts (which would inevitably mean objectionable noise) and should minimize cavities in the upper surface that can accumulate litter and possibly foul the operation.

i. if the assembly is unable to break accumulated ice,

it must provide for active heaters.

j. The parts should be economical to fabricate. in-

stall, inspect, maintain, and replace-to the extent practical while satisfying the other requirements. Studies strongly suggest that there is no feasible solution to this problem which would permit a single "bridge" structure to satisfy the entire range of variation, which is some 43 mm. The present solution is to have a family of similar bridge members, each of which provides the 18 mm. expansion allowance and a portion (in this case one-fourth) of the remaining allowance for tolerances and gentle curvature.

FIGS. [8-24 illustrate a solution by this invention of the expansion joint problem. This involves a pair of identical members (which may be referred to as blades) which fit together in hermaphrodite manner (each member having both male and female elements) to resist bending in the lateral, downward, and upward directions. Their combined upper portions, in cross section, are the profile of a standard railhead to provide rolling support and guidance to the wheel of a car; and also to clear (or engage with) the safety books of the car. Their lower portion is a foreshortened substitute for a conventional rail, in order to permit the pair of blades to transmit vertical, lateral, and even torsional loads into the adjacent beams. Connection to the beam module is at the rail itself, to minimize tolerance accumulations and take advantage of the bulk/strength residing there and the connection is such as to permit slight rotation in the plane of the rail web. Lateral-load transfer to the beam modules is by direct engagement between a male lug of the blade and a female slot machined into the railhead. Rotational loads can be resisted by engagement with the walls of this slot, together with lateral load transfer at a lower key, which will be discussed further. Rolling loads, i.e., loads parallel to the rail web, are conducted directly into the web via the same key.

The blades, together, accomplish a telescoping action to satisfy the intended variation of some 30 mm. Thus, one blade attaches to a first beam module and the second blade attaches to the second beam module. Construction of the blades would be simpler if the lugs were offset from the center of the rail, but the attendant torsional loads and unsymmetrical loading makes this appear unattractive. Further, it is mechanically advantageous to enlarge the section of each blade as its lug end is approached. Finally, the besm-to-blade gap implicit in this solution is objectionable from a structural and/or vlsiual standpoint. Therefore, the preferred solution has a lug that is essentially centered and an internal design to give continuity of back-up structure behind this lug.

Each blade has a multiplicity of mating lugs and slots in its, lower area to transfer both upward (hook) and downward (wheel) loads in the order of 5 KO. These must be long enough, in concert, to preserve adequate engagement with each other through the full range of adjustment and must have sufficient strength/bearing area to carry the greatest transfer loads, which are found to exist when the pair of blades are extended to the maximum.

Lateral loads are arbitrary. pending results of actual experience with the system. It is assumed that rolling loads from the wheel profile can cause some tendency to separate laterally at the rail surface; accordingly, the main provision for lateral engagement between the blades is located near the upper surface. Thus the present solution has a hook" that extends laterally and then downward from each blade near its lug end (again contributing to the build-up of cross-sectional area at the lug end). The opposite end of the blade has material cut away to receive the hook of its twin. Details of the hook and recess have been selected after consideration of methods for machining one part, assembling a pair together, and operational failure modes.

The preferred arrangement is shown to have the blade extend over the entire width of the railhead at its lug end. This seems particularly desirable from the standpoint of appearance and noise (as abrupt changes in support to the wheel are minimized), even though it may be somewhat more difficult to machine than alternatives. The portion of the rail-surface gap that is closer to the centerline of the rail may be either rectangular (again favoring convenience of machining) or parallelogram in nature; if it is rectangular, it follows that there are two identical rectangular gaps in staggered relationship on opposite sides of the rail centerline.

It is contemplated that four sets of the blades may be needed to make up the entire family. The first set satisfies hot-day rail gaps 2 mm. to 14 mm.; the second, 14 to 27 mm.; the third 27 to 39 mm.; and the fourth, 39 to 52 mm. Inasmuch as 52 mm. exceeds 2 mm. by the desired 50 mm., the requirement of i 25 mm. (apart from temperature variation) is therefore satisfied. The several lengths involved are seen to lend themselves to virtually the same forging and (automatic) machining techniques.

To preclude rattles and supplement transverse clamping betwen the two blades, the construction includes a spring-steel clamp that grips the lower extremity of the blades. The clamp is slidable relative to at least one of the two blades, and must not work along to an undesired longitudinal position. The present solution calls for pinning the clamp to one of the two blades, with a pin that is easily engaged, disengaged, and inspected.

In regions where accumulate ice is a significant problem, the clamp may incorporate an electrical heater. Heat is conducted through the clamping interface into the pair of blades, to preclude ice deposit.

To prevent the blade from lifting, a cross-pin engages with the projection of the main railhead on both sides of the blade lug. The key, previously mentioned, also serves to transfer longitudinal loads between the main rail and the corresponding blade, to cause the blades to telescope as desired. The rail cutaway needed for this joint is shown in FIG. 19; it provides a slotted projection of the railhead for the blade lugs, a locally machined lower surface of the railhead to engage with the cross-pin, a recess for the key, etc. The foot of the rail and as much as practical of the web extend underneath the expansion joint blades almost to the center of the overall joint, in order that the beam-end and its associated structure will be near that of the adjacent beam. This is desirable mainly because the two beam modules bear on a common column, transferring their load through a common mount. All beam modules whether curved or straight, may have this same cutaway in the interest of interchangeability and replaceability.

The objectives are thus satisfied. A crucial point is that a single, blunt rail-surface gap of some 30 mm., which would almost surely be to noisy even if mechanically sound, is avoided by substituting a parallelogramshaped gap that affords support to 50% or more of the wheel profile at any given wheel position or, alternatively, subdividing the gap into several small gaps in a staggered arrangement to achieve the same result.

Referring to FIGS. 1824, there is indicated at 201 an expansion joint of this invention positioned in the gap 203 between the ends of two rails R of a track of the railway system of the invention. The beam modules 1A are mounted on the columns or pylons 17 with appropriate gaps 203 between the ends of the rails R on the beam modules. As shown in FIG. 19, each rail R has a portion of its head 5 and its webs 23 cut away as indicated at 205, so that its base or flange 21 and a part 207 of its web project beyond the end of the rail head 5. Also, a portion of the end of the web 23 of the rail is cut away under the end portion of the rail head so as to provide a recess 209 in the end of the web under the end portion of the rail head. The upper edge of the projecting portion 207 of the rail web 23 resulting from the cutaway 205 slopes down from the lower edge of the recess as shown in FIG. 19. which The expansion joint 201 comprises an end extension or blade member 211 for one of the two rails R shown in FIGS. 18 and 19, and an end extension or blade member 213 for the other of these two rails each extension being secured at one end to the end of the respective rail and extending across the gap toward the end of the other rail. The two extensions 211 and 213 are generally identical, each comprising a web or blade 215 with an inside face 217 in sliding engagement with the web or blade 215 of the other extension and a head 218 on the web. The webs or blades 215 of the two extensions 211 and 213 are generally aligned with and extend between the ends of the webs 23 of the two rails R, overlying the projecting parts 207 in the rail webs (and the projecting parts of the rail flanges 21). Each web 215 has a laterally offset tongue 219 at its rail end received in a notch 221 in the projecting end of the respective railhead S with a sliding fit, and extending down into the recess 209. Each extension (211, 213) is pivotally mounted at its rail end on the end of the respective rail R for pivoting on an axis transverse to the rail by means of a key 222 pivotally mounted in a semicircular recess 223 at the lower edge of the recess 209, the tongue 219 at its lower edge interfitting with this key as indicated at 225. The tongue 219 is held against upward movement off the key 222 by means of a stop 227 constituted by a pin pressed in a hole 229 in the tongue underlying the projecting end of the railhead 5.

The webs 215 of the extensions 211, 213 have slidably interengaged longitudinal tongue and groove interconnections at their inside faces 217 for transmission of rolling and derailment loads (e.g., vertically, both up and down, as viewed in FIG. 19) the tongues being indicated at 231 and the grooves at 233. These resist bending of the extensions 211, 213 in the plane of the rails and are long enough for this purpose in all 

1. A railway system comprising a beam, a track extending longitudinally of the beam along one side of the beam, said track comprising a lower rail extending longitudinally of the beam adjacent the bottom of said side of the beam and an upper rail extending longitudinally of the beam adjacent the top of said side of the beam, each rail having a head, said side of the beam being inclined downwardly and outwardly from top to bottom of the beam, the lower rail projecting upwardly and outwardly from said inclined side of the beam adjacent its bottom and the upper rail projecting outwardly from said inclined side of the beam adjacent its top with the heads of the rails displaced laterally as well as vertically and lying in an inclined plane spaced outwardly from and lying above said inclined side of the beam with subsTantially all of the beam lying below said inclined plane of the rail heads, a car adapted to travel on the track alongside the beam, means at the side of the car toward the beam for supporting and guiding the car on the head of the lower rail, and means extending from the car above said inclined plane of the rail heads interconnecting the car and the head of the upper rail for holding the car against overturning, substantially all of the car being above said inclined plane of the rail heads.
 2. A railway system as set forth in claim 1 wherein the car supporting and guiding means comprises inclined wheels that engage the head of the lower rail, one wheel ahead of the center of the car and one wheel behind the center of the car, said lower rail and wheels being in a plane inclined to the vertical oppositely from the inclined plane of the rail heads.
 3. A railway system as set forth in claim 1 wherein the beam is of triangular form in cross section, having a base and inclined sides converging to an apex, the first track being on one of said sides, the beam having a second track on its other side comprising lower and upper rails symmetrically opposite the lower and upper rails of the first track, the heads of the lower and upper rails of the second track lying in a second plane inclined oppositely to the inclined plane of the rail heads or the first track with substantially all of the beam lying below said second plane, the two upper rails projecting outwardly in opposite directions adjacent said apex.
 4. A railway system as set forth in claim 3 having second and third beams meeting at a junction with the first beam and each corresponding to the first beam, the tracks of all the beams being generally at the same angle of inclination, first means for switching cars between the first track of the first beam and the first track of the second beam or the first track of the third beam, and second means for switching cars between the second track of the first beam and the second track of the second beam or the second track of the third beam.
 5. A railway system as set forth in claim 3 wherein the lower rails are structural elements of the beam and constitute lower chords situated at lower corners of the beam and the upper rails are structural elements of the beam and constitute an upper chord for the beam at the apex.
 6. A railway system as set forth in claim 1 wherein the center of gravity of the car is so situated relative to the head of the upper rail as to cause the car to tend to rotate away from the beam under all normal conditions, the car being held against overturning by means of a traveling tension-transferring interconnection with the head of the upper rail, the weight of the car having a vector generally in the plane of the lower rail and a tension vector in said interconnection, said vectors forming a triangle with said inclined plane of the rail heads.
 7. A railway system as set forth in claim 6 wherein the tension-transferring interconnection comprises at least one roller which engages an inward-facing surface on the head of the upper rail.
 8. A railway system as set forth in claim 7 wherein there are a plurality of rollers, some above and some below the web of the upper rail.
 9. A railway system as set forth in claim 8 wherein the several rollers are mounted on a common carriage, which carriage partially encircles the head of the upper rail.
 10. A railway system as set forth in claim 9 wherein there is also mounted on the carriage a device to collect electrical power from a third rail mounted in proximity to the head of the upper rail.
 11. A railway system as set forth in claim 10 wherein the third rail is mounted on the bottom of the web of the upper rail, and is connected to an electrical power bus at periodic intervals along the track.
 12. A railway system as set forth in claim 1 wherein the tension-transferring interconnection comprises means enabling transition of the upper and lower rails to difFerent relative displacements while retaining the car erect.
 13. A railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, wherein the beam has a second track comprising third and fourth rails symmetrically opposite the first and second rails, the heads of the third and fourth rails lying in a second plane inclined oppositely to the first plane with substantially all of the beam below said second plane, wherein the lower rails are structural elements of the beam and constitute lower chords situated at lower corners of the beam and the upper rails are structural elements of the beam and constitute an upper chord for the beam, and wherein the beam has three shear-carrying webs in isosceles triangle arrangement, each web connecting two of the chords.
 14. A railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, having a car adapted to travel on the track, means for supporting and guiding the car on the head of the lower rail, and means interconnecting the car and the head of the upper rail for holding the car against overturning, substantially all of the car being above said plane, wherein the car supporting and guiding means comprises inclined wheels that engage the head of the lower rail, one wheel ahead of the center of the car and one wheel behind the center of the car, and having hooks along side each wheel, said hooks extending generally downward parallel to the plane of the wheel and inclined toward each other, partially encircling the head of the lower rail.
 15. A railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, having a car adapted to travel on the track, means for supporting and guiding the car on the head of the lower rail, and means interconnecting the car and the head of the upper rail for holding the car against overturning, substantially all of the car being above said plane, wherein the center of gravity of the car is so situated relative to the head of the upper rail as to cause the car to tend to rotate away from the beam under all normal conditions, the car being held against overturning by means of a traveling tension-transferring interconnection with the head of the upper rail, and wherein there is one tension-transferring interconnection ahead of the center of the car and one such interconnection behind the center of the car, with each interconnection being capable of extension and retraction, and means adapted to cause one to extend as the other retracts.
 16. A railway system as set forth in claim 15 wherein the said means comprises a hydraulic cylinder in each interconnection, and a hydraulic connection between the two hydraulic cylinders.
 17. A railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, having a car adapted to travel on the track, means for supporting and guiding the car on the head of the lower rail, and means interconnecting the car and the head of the uPper rail for holding the car against overturning, substantially all of the car being above said plane, wherein the center of gravity of the car is situated relative to the head of the upper rail as to cause the car to tend to rotate away from the beam under all normal conditions, the car being held against overturning by means of a traveling tension-transferring interconnection with the head of the upper rail, and wherein the said interconnection is mounted to move up and down relative to the car, adapting it to various heights of the head of the upper rail relative to the head of the lower rail.
 18. A railway system as set forth in claim 17 wherein the up-and-down motion is generally rotational about an axis adjacent the intersection between the plane of the car''s wheels and a vertical longitudinal plane including the center of gravity of the car.
 19. railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, wherein the beam has a second track comprising third and fourth rails symmetrically opposite the first and second rails, the heads of the third and fourth rails lying in a second plane inclined oppositely to the first plane with substantially all of the beam below said second plane, having second and third beams meeting at a junction with the first beam and each corresponding to the first beam, the tracks of all the beams being generally at the same angle of inclination, first means for switching cars between the first track of the first beam and the first track of the second beam or the first track of the third beam, and second means for switching cars between the second track of the first beam and the second track of the second beam or the second track of the third beam, wherein each switching means has two tracks and wherein the four tracks of the switching means, in transverse cross-section, are disposed two on one side and two on the other of triangles of progressively increasing size.
 20. A railway comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, wherein the beam has a second track comprising a third and fourth rails symmetrically opposite the first and second rails, the heads of the third and fourth rails lying in a second plane inclined oppositely to the first plane with substantially all of the beam below said second plane, having second and third beams meeting at a junction with the first beam and each corresponding to the first beam, the tracks of all the beams being generally at the same angle of inclination, first means for switching cars between the first track of the first beam and the first track of the second beam or the first track of the third beam, and second means for switching cars between the second track of the first beam and the second track of the second beam or the second track of the third beam, and wherein a third rail for power distribution is mounted beneath the upper rail of each of the four tracks throughout the switching area.
 21. A railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, wherein the beam is elevated above a floor of a station, and wherein a car has an elevator adapted, when the car is stopped at the station, to descend to said floor for ingress and egress of passengers, and having guard means at said station for keeping people out from under the descending elevator, said guard means extending upwardly from said floor to a height sufficient to exclude people from the area under a descending elevator, and being movable downwardly by the elevator as it descends.
 22. A railway system comprising a beam, a track extending longitudinally of the beam, said track comprising a lower and an upper rail extending longitudinally of the beam, each rail having a head, the heads of the rails lying in a plane inclined to the longitudinal vertical plane of the beam with substantially all of the beam below said inclined plane, having expansion joints in gaps between the ends of successive rails, each rail having a base, a web and a head, each expansion joint occupying the gap between the ends of two rails and comprising an end extension for one of the two rails and an end extension for the other, each extension being secured at one end to the end of the respective rail and extending across the gap toward the end of the other rail, each extension having a web with an inside face in sliding engagement with the inside face of the web of the other extension, with the webs of said extensions generally aligned with and extending between the ends of the webs of the two rails, the webs of said extensions having slidably interengaged longitudinal interconnections at their said inside faces for transmission of loads perpendicularly to the length of the webs of the extensions in the plane of the latter, each extension further having a head on its web in extension of the head of the respective rail, the head of each extension extending from adjacent the end of the respective rail toward but terminating short of the end of the other rail, and the heads of the extensions having opposed angled ends at an expansion gap therefor.
 23. In a railway system, a common track and first and second branch tracks, a car adapted to travel on the tracks, and switch means for switching the car for travel either on the common and first branch tracks or the common and second branch tracks, each of said tracks comprising a pair of rails, means supporting the rails of said tracks with the rails displaced both vertically and laterally relative to one another so that the heads of the rails lie in an inclined plane, said supporting means lying substantially wholly below said inclined plane, said switch means comprising a first pair of fixed switching rails associated with the first branch track, a second pair of fixed switching rails associated with the second branch track, and a pair of movable rails for switching the car between the common track and first pair of fixed switching rails and between the common track and the second pair of fixed switching rails, and means supporting the fixed and movable switching rails with these rails displaced both vertically and laterally relative to one another and lying in substantially the same inclined plane as said common and branch tracks, the movable switching rails being movable in said inclined plane, said car having means for supporting and guiding it on the lower of each of said pairs of rails, and means extending from the car above said inclined plane for interconnecting the car and the upper of each of said pairs of rails for holding the car against overturning.
 24. In a railway system as set forth in claim 23, said movable switching rails being short in length relative to said fixed switching rails.
 25. In a railway system as set forth in claim 23, each of said common track and said first and second tracks being on a beam, said beams meeting at a junction. 